The option that best describes a government action to assist closed captioning, based on the excerpt from the Television Decoder Circuitry Act of 1990, is:
It required all manufacturers of 13-inch or larger TVs to include built-in decoder circuitry for receiving closed captioning broadcasts.
This aligns with the amendment in the act specifying that TVs manufactured or imported for use in the United States must have the necessary decoder circuitry for closed captions.